Process of preparing leather.



UNITED STATES PATENT oEEIoE.

PHILIP MAGNUS, OF NORTHCOTE, AND TIMOTHY JOSEPH DAVIS, OF NORTH FITZROY, VICTORIA, AUSTRALIA, ASSIGNORS TO .THE RUBBERIZED LEATHER AND TYRE UOMPAN Y LIMITED, OF MELBOURNE, AUSTRALIA.

PROCESS OF PREPARING LEATHER.

To all whom it may concern:

Be it known that we, PHILIP MAGNUS, collector, a resident of 103 Union street, Northcote, and TIMOTHY J OSEPH DAVIS, artist and photographer, a resident of 8 Grant street, North Fitzroy, in the county of Bourke, State of Victoria, and Commonwealth of Australia, subjects of the King of Great Britain and Ireland, have invented a certain new and useful Process of Preparing Leather, of which the following is a specification.

Our invention relates to improvements in the invention the subject of prior United States Letters Patent granted to Philip Magnus, numbered 775,839 and dated November 22, 1904; and the object is to so treat leather that a material is produced which is more durable and waterproof and less affected by exposure to the sun and rain or weather. The product, while it retains its pliancy is yet waterproof, and, in addition, it

acquires a resisting power which renders it much less liable to puncture and rupture. It is also of much 'more resiliency.

Our invention includes leather of any ordinary character. The leather is preferably taken directly from the tanning or'preserving pits in its'wetstate and is softened in any wellknown way, the object being to prevent cracking or hardening and to preserve a softened article when the following treatmentdryingis gone through. After having been softened it is well stretched and dried, either artificially or naturally. In either case it is dried-slowly, so that the pores or cells in the leather are not impaired. After having been dried the leather is well buffed up or chafed on the flesh side, the object being to open the pores of the leather as much as possible. The leather is then treated with a clarifying'solution, the object being to eradicate all original fatty matter still remaining in the leather or from what may have been absorbed when the leather was being treated for softening, as above described. This softening solution is made up as follows: About four (4) parts, more'or less, of chlorid of sulfur are dissolved in ninety-six (96) parts, more or less, of carbon bisulfid. The mixture iswell agitated and allowed to remain for twenty-four (24) hours, more or less. The liquid is then poured off into a receptacle. The residue is discarded. By residue we Specification of Letters Patent.

Application filed September 19, 1905. Serial No. 279,155.

(Specimens) refer to any powdered sulfur that has not been dissolved in the carbon bisulfid. The mixture, as said, should be as clear a liquid as possible.

To about ten (10) parts, more or less, of the mixture is added about ten ounces of benzol, about four ounces of ether sulfuric, about three ounces of rectified benzin, about eight ounces of naphtha, about two and one-half ounces of rectified spirits of turpentine, and about two and one-half ounces of'kerosene. The above amounts are approximate, as the proportions mayvary according to the am ount of sulfur that may settle to the bottom of the receptacle. If when the above amounts are added the said sulfur should show a tendency to rise or cloud, the parts will have to be reduced proportionately, as it is essential that the mixture used to clarify be perfectly clear, so as not to impair the pores of the leather. By the word settle is meant recipitationthat is to say, although the bisulfid of carbon which has absorbed the chlorid of sulfur is apparently clear, yetwhen the benzol, ether sulfuric, rectified benzin, naphtha, rectified spirits of turpentine, and kerosene are i added a further precipitation is liable to ensue, and the quantities may be varied so as to prevent this. The exact quantity rests with the operator. The mixture requires tobe as strong as possible and have as much sulfur aspossible; but this sulfur must be, as said, absorbed in the mixture.

By using the chlorid of sulfur we find that not only does it assist to render the leather easier to impregnate with the rubber, as hereinafter described, but it also preserves the said rubber when introduced into the. pores of the leather. The chlorid of sulfur, which is introduced into the leather before the rubber, tends to preserve the said rubher after it has been impregnated into the leather, sulfur being the best known preservative of rubber. The mixture is such that it will not injure the fibers of the leather, nor, which is more important still, will it fill up or close the said cells or pores of the leather. If the mixture clouds or is not perfectly clear, it will at once be apparent that the powder will seal the pores of the leather and prevent the entrance of the rubber.

A pint, more or less, of the mixture is taken from the receptacle, and to it is added termed the first rubber solution.

four (4) gallons, more or less, of benzin. This constitutes the solution to clarify the leather. The clarifying mixture is a strong one, and if the leather were permitted to be immersed in the mixture for any length of time it would ruin the fibers of the leather or it must damage it considerabl The mixture must be strong, so as to thoroughly remove all fatty matter or impurities from the leather. We fino in operatlon that it is sufficient to spray the mixture upon the leather, or, if the leather is introduced into the mixture, it should only be just in and out again. The operator must necessarily use his good judgment according to the nature of the leather.-

The clarifying solution is either sprayed or sprinkled onto the leather, or theleather may be bathed therein for a few minutes, more or less. After having been so treated the leather is taken out and thoroughly dried. It is essential that the leather be dried until it is bone or warm dr It is then ready for treatment with the st of the rubber solutions.

The leather is now placed in what is This is the thinnest of the baths, the object being to get the rubber into the smallest and innermost pores and those nearest the outer or hair side. The following operations are all conducted in a room or chamber the tem perature of which is kept at about one hundred (100) degrees Fahrenheit. It must be understood that the following proportions are based upon the use of the best pararubber. If inferior pararubber is employed, the quantity of naphtha used to dissolve the rubber may be lessened. This first rubber solution contains about six parts of pararubber, about sixty-eight parts of naphtha, about twenty-four parts of benzin, and about two parts of benzol.

In some cases the quantity ofben'zol ma be diminished, dependent upon the strength of the naphtha employed. N aphtha iscommercially more ex ensive than benzin. Naphtha by itse if maybe used and benzin dispensed with. The reason benzin is employed is because it is cheaper than na htha, and once the rubber has been disso vedby the naphtha it can be thinned by benzin. We find that the strength of naphtha varies considerably. Whether it is dependent upon the age or the manufacture we do not know. If the naphtha is of the best quality, the quantit of benzol may be diminished. Should t e naphtha be a poorer quality, then more benzol is desirable.

The solution is made up as -follows: The pararubber is dissolved by the'naphtha and the mixture thinned by adding the benzin. It is then further thinned by adding benzol.

The above solution, which We will for convenience term the first rubber solution is of a consistency like unto milk. It is laced in an air tight bath tank. The ihather is placed therein, and the tank made air-tight. The leather is allowed to remain submerged in the bath for about forty-eight (48) hours; but the time will depend u on circumstances, the description of the leat ier treated, and the strength of the solution. At regular intervals of about twenty-four (24) hours the leather may be taken from the air-ti ht tank, placed upon a bench, and well wor ed up by hand and put back again into the solution, or instead of the leather being taken out and-worked up as described, agitators may operate within the tanks, which agitatorswill automatically perform the working-up operation. At the end of about forty-eight (48) hours the leather is rendered translucent, or has a tendency to transparency when held to the light. The effect of the immersion in this first solution of rubber is to make the leather almost transarent. The actual duration of immersion is regulated b the quality and thickness of the leather. ilVhen the leather has reached this stage of trans arency,-it is lifted out of the solution and allowed to drip for five (5) or ten (10) minutes, more or less. Then it is ready for immersion in the second rubber solution. This second rubber solution consists of about six parts of pararubber, about eighty parts of naphtha, about eleven parts of benzin, and about three parts of benzol.

In some cases the uantity of benzol may be diminished, depen out upon the strength of the naphtha used, as above ex lained.

The solution is made up as ollows: The pararubber is dissolved by na htha, and the mixture thinned by adding t e benzin. It is then further thinned by the benzol. This second rubber solution is of thicker consistency than the first rubber solution, owing to the higher percentage of rubber therein, and is like unto a thin cream. The second rubber solution is also placed in an air-tight bathtank.

The leather in a wet but not dripping state is placed directly into the tank containing the second solution, submerged therein, and the tank made air-tight. Some descriptions of leather may require to be taken out once or twice or worked up, as previously described. Some classes of leather may require more working up than others. The classes and "descr1ptions referred to means the class of leather employed. It is much easier to introduce the rubber into chrome-tanned leather; but if the leather has been bark-tanned then it must be worked up as described or repeatedly submerged. Then, again, the animal from which the hide has come is included in this term. The ox-hide may reriuire more treatment than kangaroohide, a uifalo more than an ox, and a ratskin would not require the same length of treatment as a horse-hide. This second rubber solution ermits the larger pores toward the inner or fliash side to become filled. With a view to making the treatment more effective agitation may be here used. Agitation after any or all the baths may be used to more thoroughly permeate the leather Where deemed to be necessary.

After forty-eight (48) hours submersion in the abovesecond rubber solution the leather is taken out and allowed to drip for about five (5) or ten (10) minutes, more or less, and is then ready for treatment with the third and final solutions. j

The next bath consists of a solution thicker than the two previous ones, more rubber being firesent. It is intended in this condition to 1 up the outer and more open pores on the flesh side. This third rubber solution, which is the thickest of the solutions mentioned, is of the consistency of a thick cream. It consists of about six parts of pararubber, about eighty-eight parts of naphtha, about four and one-half parts of benzin, and about one and one-half parts of benzol.

In some cases the quantity of benzol may bediminished, dependent upon thestrength of the naphtha used, as above. explained The solution is made up as follows: The pararubber is dissolved by the naphtha and the mixture thinned by adding the benzin. Benzol is added to still further thin the solution to the desired consistency, which is, as said, like unto a thick cream. The solution is placed in an air-tight revolving drum, which is provided within its interior with paddles, beaters, a itators, or the like and has a gas-escape val ve therein. The leather in a wet, but not dripping, state is placed in the solution in this drum, which is rotated by suitable means. This drumming serves a twofold purposeviz., to assist in driving or injecting into the leather the thicker solution of rubber where anypores have not completely filled and to effect a softening of the leather. The leather remains in the said drum for from twenty-four (24) to fortyeight (48) hours, more or less, after which it is taken out andallowed to gradually become semidry. It is then put through rollers for the purpose of better cementing the parts. After this it is dried, and the operations are complete.

Having thus'fully described the invention, what we claim is 1. The herein-described process of treating previously tanned andsoftened leather, consisting in first subjecting it to a cleansing or clarifying solution to eliminate all. fatty matters; second immersing it in a solution containing a small percentage of rubber to fill the smallest and innermost pores andthose nearest the outer or hair side; third, immersing it in a second bath containing a larger percentage of rubber to fill the larger pores towardthe inner or flesh side of the leather; fourth, immersing it in a third solution containing a still greater proportion of rubber to fill up the outer and most open pores on the flesh side; and finally drying it substantially as and for the purpose setforth.

2. The herein-described process of treating previously tanned softened and dried leather, consisting infirst, subjecting it to a clarifying solution containing chlorid of sulfur to facilitate impregnation of the leather with rubber and to preserve the rubber; then drying the leather; second immersing it in a solution composed of hydrocarbon solvents and a small percentage of rubber until the leather is substantially transparent; third, immersing the leather in a second bath composed of hydrocarbon solvents and a larger percentage of rubber; fourth, immersing the leather in a third bath composed of solvents and a larger percentage of rubber and agitating it while so immersed; and finally drying the leather, substantially as described.

3. The herein-described process of rubberizing leather, consisting in taking leather previously dried and softened, treating it with a clarifying solution to remove any remaining fatty matters second, treating the leather in an air-tight tank with a solution composed of hydrocarbon solvents and rubber; third, placing the leather in a second air-tight tank containing a similar solution contalnmg a larger percentage of rubber and treating it therein; fourth, placing the leather in an air-tight receptacle containing a similar solution having a greater percentage of rubber; and stirring or drumming the leather therein; and finally removing and drying the leather, substantially as described.

4. The herein-described process of making rubberized leather consisting in taking pre- .viously softened and dried leather, bufling it on the flesh side, then subjecting it to the action of a clarifying solution containing chlorid of sulfur and carbon bisulfid, then drying the leather; then immersing the leather in an air-tight tank in a bath com posed of pararubber, naphtha, benzin and b'enzol, and working the mixture into the leather; then removing the leather from such first rubber solution, letting it drip, and placing it in a wet state in a second air-tight tank containing a similar rubber solution in which there is a greater percentage of rubber; then removing the leather and letting it drip, and, placing it in a Wet state in an air-tight receptacle containing a similar rubber solution having a still greater percentage of rubber, and working or stirring the leather in such solution; then removing the leather, partly drying it, and finally running it between rollers and drying it, as set forth.

5. An improved leather, and the hereindescribed process of pre aring the same, consisting of leather which 1s softened, stretched.

and then dried either artificially or naturally; then buffed up on the flesh side, and then sprayed or sprinkled with or bathed in a clarifying solution composed of chlorid of sulfur dissolved in carbon bisulfid, prepared and treated as described, and allowed to remain for twenty-four (24) hours, more or less, when there is added to a proportion of it, benzol, ether sulfuric, rectified benzin, naphtha, rectified spirits of turpentine, and kerosene, which mixture, in the parts mentioned, is added to a further amount of benzin as prescribed; then thoroughly dried, then in a room'or chamber of the temperature of 100, more orless, Fahrenheit, immersed for forty-eight (48) hours, more or less, in an air-tight tank containing a solution of the consistency like unto milk, and made u of the herein-mentioned proportions 0 ararubber, naphtha, benzin, and benzol, W ich mixture is worked into the leather in the manner described until the said leather is rendered transparent or has a tendency to' transparency; then taken out and allowed to drip, then in a wet state, and in a room or chamber of the temperature mentioned, immersed for about forty-eight (48) hours, more or less, in a second air-tight tank containing a solution of a consistency like unto a thin cream, and composed of the herein-mentioned proportions of pararubber, naphtha, be'nzin or benzol; then taken out, and if necessary worked or treated in the manner described; then allowed to drip then in a Wet state, and in a room or chamber of the temperature mentioned placing into a revolving drum of the character described containing a solution of a consistency like unto a thick cream, and composed of pararubber, naphtha, benzin, and benzol; immersed therein for a eriod of from twentyfour (24) to forty-eig t (48) hours, more or less; then taken out and semidried; then put through rollers, and finally dried, all as and for the purposes hereinbefore described;

In testimony whereof we aflix our signatures in the presence of two subscribing witnesses.

PHILIP MAGNUS. TIMOTHY JOSEPH DAVIS.

Witnesses: v I

CECIL MGSLASTRIEL, GEORGE A. MoREN." 

